Compressor



Dec. 1, 1959 A. M. STENGER 2,915,241

COMPRESSOR Filed Oct. 15. 1957 INVENTOR AUGUST M. STENGER HIS ATTORNEY.

2,915,241 COMPRESSOR sell-Rand Company, New York, N.Y., a corporation of New Jersey I Application OctoberlS, 1957, Serial No. 690,394

7 Claims. (Cl. 230-172) The invention relates to compressors, and more particularly to an'air or gas compressor of the reciprocatyp An object of prime importance in this invention is to separate the crank case chamber completely from the cylinder bore to prevent the lubricant to contaminate the gas to be compressed.

Another object is to utilize the means for separating the crank case chamber from the cylinder bore to act as a'surge pump for improving the cooling of the cylinder.

lAnother object is to utilize the means for separating the crank case chamber from the cylinder bore to cause a surging of air through the crank case chamber.

Still another object is to prevent dust or other impurities to accumulate on the coolingribs or outer cylinder wall to affect the cooling thereof.

Another object is to provide means to improve the cylinder cooling and at the same time simplifying the filtration of the intake air to be admitted into the com-- pressor for compression. 7 I

With the above and other objects in view, the invention may include the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

. In the drawings:

Figure 1 is a cross sectional view of the compressor along the line'1--1 of Fig. 2 looking in the'direction of the arrows, and

Fig. 2-is a vertical sectional view of the compressor along the line 2-2 of'Fig. 1 looking in the direction of the arrows.

Referring more in detail to the figures of the drawing, there is shown at 10 acrank case within which is mounted for rotation on a horizontal axis a shaft 12. On the shaft 12 is journaled an eccentric disc 14 which actuates an eccentric rod 16 for reciprocating a crosshead 18. Supported on a flanged top 20 of the crank case 10 is a cylinder 22 provided at its lower end with a flange 24 to which the flanged top 20 is bolted through bolts 26. The cylinder 22 comprises a bore 28 within which a piston 30 operates. It is to be observed that the central portion of the piston 30 has been extended to form a stem-like extension 32. As shown in Fig. 2 the piston stem 32 is connected to the top of-the crosshead 18 through astud 34 and secured by a locking stud 35.

A flexible diaphragm 36, concerning one of the major features of this invention, is provided to serve a dual. purpose. One purpose is to seal off the cylinder bore 1 28 fror'n'the' interior of the crank case 10 to preventthe lubricant to be splashed against the inner cylinder wall and thereby contaminating the air to be compressed.

The other purpose of the diaphragm 36 is to act as a surge pump to improve the performance of the compressor.

Referring more in detail to the structural arrangement of the diaphragm 36, Fig. 1 shows the connection between the piston 30 and the crosshead 18 in which the central part of the diaphragm 36 is clamped between the piston stem 32 and the top 38 of the crosshead 18. The outer margin 40 of the diaphragm 36 is clamped between the cylinder flange 24 and the flanged top 20 of the crank case 10. In this manner the diaphragm 36 completely separates the cylinder bore 28 from the crank case chamber 42 and the lubricating oil in the crank case 10 will be prevented from splashing against the inner cylinder wall and consequently the air to be compressed will be free of contamination.

In addition to this protective feature, the diaphragm 36 also acts as a surge pump and receives its motion from the reciprocating piston and crosshead 18 to which it is connected. This additional feature of the diaphragm 36 relates to a forced air cooling system and will be explained hereinafter.

It is to be noted that while no oil is splashed on the inner cylinder wall, the lubrication thereof has been provided for by using a piston ring 44 of the self lubricating type.

In order to provide a more eflicient cooling of the cylinder 22 a forced air cooling system is produced. For this purpose, the cylinder 22 is provided, over its entire periphery, with cooling ribs 46 which are suitably arranged and calculated to effect a good heat exchange between the cylinder 22 and the surrounding air. a

I As illustrated in Fig. 1, the cooling ribs 46 are arranged flange 50, to which a cylinder head 23 including the exhaust valve 27 is connected. An intake valve 25 of the common flexible ring plate type is connected to the upper end of the upper'flange 50 by screws 62, of which only one is shown, 180 apart so that in operation the intake valve 25 flexes from the points of connection. Between the flange 50 and the flange 24 at the lower end of the cylinder 22, the filter screen 48 is snugly fitted'while it also fits around the cooling ribs 46. In this manner a compartmentSZ is formed between two consecutive cooling ribs 46. A number of these compartments 52 are'in communication with the space between the piston 30 and the diaphragm 36 by means of ports 54 positioned in the lower cylinder flange 24 and having its upper end arranged between the lower ends of two consecutive cooling ribs 46.

In operation, the diaphragm 36 is actuated by the reciprocating piston 30 and crosshead 18 and makes a pumping motion. Thispumping motion causes a surge of air through the ports 54, and during the upward stroke of the diaphragm 36 the air in the compartments 52 is forced out through the filter screen 48 and into the atmosphere. During its downward stroke cool air will be drawn through thefilter screen 48 and into the compartments 52 where it absorbs the heat radiated by the adjacent cooling ribs 46 and part of the outer cylinder wall 47. It is clear that this system of swish cooling l will force the air to flow over the entire inner surface of the compartments 52, thereby effecting a perfect cooling of the cylinder 22 and contributes greatly to the improvement of the compressor performance.

The pumping motion of the diaphragm 36 is also utilized to swish cool the crank case chamber 42. In order to achieve this, a surge port 56 is provided and positioned in the upper part of the crank case Iii such that the crank case chamber '42 is in communication with the space directly under the diaphragm 36. When the diaphragm 36 is actuated, the pumping motion thereof will cause the air to surge back and forth through the surge port 56 and effect a swish cooling of the crank case 10.

An important advantage of the provision of the filter Patented Dec. 1, 1959 Screen 48 around the cooling ribs 46 is that the air, being the medium to accomplish the cooling of the cylinder .22, is kept clean and free of dust or other impurities while it surges through the compartments 52. Consequently, the inner surfaces of the compartments 52, being the cooling surfaces of thecylinder 22, will remain clean to freely radiate its heat to be carried oh by the surging air.

According to the invention, the filter screen 48 is not only provided .to filter the cooling air but also to simplify substantially the filtration of the air to be admitted to the intake valve 35. In order to achieve this, at least one passage 53 is provided and positioned in the upper flange of the cylinder 22. One end or" the passage 58 leads to the intake valve 25, and the other end of the passage 58 is in communication with one of the compartments 52. it is to be noted that this particularcompartment is not provided with the port 54 and, therefore, is only in communication with the atmosphere outside of the filter screen 48. At every suction stroke of the piston 39 the air to be compressed will be drawn through the filter screen 48 before it is conducted through the passage 58 and the intake valve 25 into the cylinder 22. As clearly illustrated, the filtration of the intake air, by utilizing the filter screen 48, is substantially sim-' plificd and eliminates the use of a separate intake filter and consequently reduces the cost of production.

The advantages of the simplified air filtration and the improved cooling system-as applied in a compressor and specified hereinbefore are numerous, and the structural arrangement and combination to provide an improved compressor to achieve these features is believed to be novel.

It is obvious that the invention is not limited to the embodiment hereinbefore described and illustrated by' way ofexample, but extends to all embodiments involving the use of the features hereinbefore set forth and fulfilling the desired requirements.

I claim:

1. in a piston type compressor, in combination, a casing member, a cylinder member provided with a bore and having one end mounted on the casing member, cooling ribs on the cylinder exposed to the atmosphere, a pistonreciprocable in the cylinder bore, means connected at one end to said piston and extending into said casingmember for reciprocating said piston, a diaphragm encircling and held in sealing relation with said means and sealed at its outer margin to one of said members to seal off the cylinder bore from the interior of said casing member, said diaphragm having a centralportion connected to said means for actuating the central portion of said diaphragm, and at least one port at. said end of said cylinder having one end opening into thespace between the piston and the diaphragm and its other end opening into the atmosphere and positioned to direct air moved by said diaphragm along at least some of said, ribs.

2. In a piston type compressor, in combination, a crank case having a chamber therein, a cylinder member provided with a bore and having one end mounted on the crank case, cooling ribs on thecylinder, a crankshaft in the crank case, a piston reciprocable in the cylinderibore, a connecting rod for connecting the crank shaft andthe piston, a flexible diaphragm having a peripheral portion clamped between the cylinder and the crank case for an air tight separation of the cylinder bore from the crank case chamber, said diaphragm having its .central portion operatively connected to the connecting rod to cause a pumping motion of said ,diaphragm,and port means at said end of the cylinder in communication with thespace between the piston and the diaphragm and with the atmosphere and positioned to direct air pumped by the diaphragm along said ribs.

3. In a piston type compressor, in combination, a casingmember, a cylinder member provided with a bore and having one end mounted on said casing member,

4 a a cylinder head mounted on the cylinder, an inlet valve in the cylinder head, cooling ribs on the cylinder, a piston reciprocablc in the cylinder bore, means connected at one end to said piston and extending into said casing member for reciprocating said piston, a diaphragm having a peripheral portion connected to the marginal portion of one of said members for an air tight separation of the cylinder bore from'the interior of said casing member, said diaphragm having a central portion connected to said means to cause a pumping motion of said diaphragm, a filter screen disposed around the outer edges of the cooling ribs to form a compartment between consecutive cooling ribs each having a surface exposed to the atmosphere, and ports at said end of the cylinder positioned to communicate at least every other of said compartments with the space between the piston and the diaphragm.

4.111 a piston type compressor, in combination, a;

casing member, a cylinder member including a cylinder inlet valvein the cylinder head, cooling ribs on the cylinder, a piston reciprocable in the cylinder bore,

means connected atone end to said piston and extending into said casing member for reciprocating said piston,

a diaphragm having a peripheral portion connected to the marginal portion of one of said members for an air tight separation of the cylinder bore, from the interior of said .casingtmember, said diaphragm having a central portion connected to said means to cause a pumping motion of said diaphragm, a filterscreen disposed around the outer edges of the cooling ribs to form a compartment between consecutive cooling ribs, and at least one port at-said end of the cylinder positioned to communicate withx-the atmospherethrough at least one of said compartments with the space between the piston and the diaphragm, and at least one passage in the cylinder at the other end of the cylinder positioned to communicate the inlet valve with the atmosphere through at least one of the other of said compartments.

5. In a piston type compressor, in combination, a

' casing member, a cylinder member provided with a bore and having one end mounted on the casing member,

a cylinder headmounted on the cylinder member, an inlet valve in the cylinder head, cooling ribs on thecylinder, a piston reciprocable: in the cylinder bore, means connected at one end to said pistonand extending into said casing member for reciprocating said piston, a diaphragm having a peripheral portion connected to the marginal portion of one of said members for air tight separation of the cylinder bore from the interior of the casing member, said diaphragm having a central portion operatively connected to the piston to cause a pumping motion of said diaphragm, a filter screen disposed around the cooling ribs to form a compartment between consecutive cooling ribs having its outer surface exposed to the atmosphere, and at least one port at said one end of the cylinder member positioned to communicate at least one of said compartments with the space between the piston and the diaphragm, and at least one passage through the cylinder positioned to communicate the inlet valve with another of said compartments,

6.111 a piston type compressor, in combination, a

casing member, a cylinder member provided with a'bore themarginal portion of one of said members for an air tight separation of the cylinder member bore from the interior of the casing member, said diaphragm having a central portion clamped between the piston and said means to be actuated thereby to cause a pumping motion of said diaphragm, a filter screen disposed around the cooling ribs to form a compartment between consecutive cooling ribs having its outer surface exposed to the atmosphere, and at least one port at said end of the cylinder member positioned to communicate at least one of said compartments with the space between the piston and the diaphragm, at least one passage through the cylinder at the other end of the cylinder member positioned to communicate said inlet valve and at least one ofthe other of said compartments, and at least one surge port positioned at said end of the casing member connected to said cylinder member positioned to permit the phragm encircling and fixedly connected to and held in sealing relation with said means and sealed at its outer margin to one of said members to seal ofi the cylinder bore from the interior of said casing member, said cylinder including spaced radially extending cooling ribs having the spaces therebetween communicating with the atmosphere, port means in the cylinder leading from air actuated by the diaphragm to surge through said a piston reciprocable 'in the cylinder bore, means connected at one end to said piston and extending into said casing member for reciprocating said piston, a diaone side of the diaphragm to between at least some of said ribs for conducting air pumped by the diaphragm to cool said some of said ribs, and air intake passage means for the compressor leading from between the remaining ribs such that air flowing to such passage means cools said remaining ribs.

References Cited in the file of this patent UNITED STATES PATENTS 2,464,560 Davey Mar. 15, 1949 2,539,896 Dalrymple Jan. 30, 1951 2,711,137 Moller June 21, 1955 FOREIGN PATENTS 216,157 Great Britain Nov. 6, 1924 714,508 Great Britain Sept. 1, 1954 1,102,573 France May 11, 1955 

